Question

I have written a program that determines the frequency of letters in an input file.

It works perfectly but the only problem is that the output file should put the characters in the order that they appear but they are being put in alphabetical order.

Please help.

Here is the code:

#include <fstream>

#include <iostream>

using namespace std;

int main()

{

   ofstream out;

   out.open("output.txt");

ifstream input("input.txt", ios_base::binary);

size_t count[256];

fill_n(count, 256, 0);

for (char c; input.get(c); ++count[uint8_t(c)])

  ;

for (size_t i = 0; i < 256; ++i)

{

  if (count[i] && isgraph(i))

  {

   out << char(i) << " " << count[i] << '\n';

  }

}

out.close();

}

Answer 1

as it is 256 char and it will have intial value of 0 so always it will start with A as asci value of A is less so it will be in sorted order, so overcome this have used vector of pairs that track char and count

#include <fstream>
#include <vector>
#include <iostream>

using namespace std;

int main()

{
    ofstream out;
    out.open("output.txt");
    ifstream input("input.txt", ios_base::binary);
    // vecor of pairs
    vector<pair<char, int>> char_map;
    char ch;
    while (input >> noskipws >> ch)
    {
        // if valid value
        if (isgraph(ch))
        {
            bool found=false;
            // finding in vector if already present
            for (pair<char, int> &it:char_map)
            {
                // if present increasing the count
                if (it.first == ch)
                {
                    it.second += 1;
                    found = true;
                    break;
                }
                
            }
            // if first time then pusing the count as 1
            if(!found){
                pair<char, int> t;
                t.first = ch;
                t.second = 1;
                char_map.push_back(t);
            }
        }
    }
    // writing to file
    for (pair<char, int> &it:char_map)
            {
                out<<it.first<<" "<<it.second<<endl;
                
            }
    out.close();
}

//SAMPLE FILE input.txt

Fredda
Sulema
Lynette
Maire
Alayna
Wanda
Celia
Long
Genia
Howard
Isadora
Hugh
Jamie
Alethea
Carola
Shea

//OUTPUT output.txt

F 1
r 5
e 11
d 5
a 17
S 2
u 2
l 5
m 2
L 2
y 2
n 5
t 3
M 1
i 4
A 2
W 1
C 2
o 4
g 2
G 1
H 2
w 1
I 1
s 1
h 3
J 1

Please do comment if u have any concern